Machine for grinding or polishing lenses



Sept. 17, l940. TAYLOR 2,214,977

DIACHINE FOR GRINDING OF. POLISHING LENSES Filed March 25, 1940 Patented Sept. 17, 1940 UNITED STATES MACHINE FOR GRINDING OR POLISHING LENSES Douglas Taylor, Ladywood, Birmingham, England Application March 25, 1940, Serial No. 325,921

In Great Britain May 13, 1939 8 Claims.

improved means for detachably securing thelap v to the spindle. Y

The invention comprises a permanent magnet adaptedto be secured to the upper end of the spindle, and to hold by magnetic attraction the removable lap or a clamp to which the lap can be attached.

In the accompanying sheet of explanatory drawings:

Figure 1 is a sectional elevation of a grinding or polishing lap detachably secured in accordance with the invention to the upper end of a vertical or substantially vertical spindle.

Figures 2 and 3 are respectively a sectional elevation and a sectional plan illustrating a modified form of the invention. (Figure 3 being taken on the line 33 of Figure 2), and Figure 4 is an elevation of the permanent magnet shown in Figures 2 and 3.

Figures 5 and 6 are respectively similar views to Figures 2 and 3 illustrating a mode of employing the invention for detachably securing to the upper end of the spindle a clamp to which I the lap is attached, Figure 6 being a section on the line 6-6 of Figure 5.

In the drawing a indicates the vertical or substantially vertical spindle which at its upper end is surrounded by the stationary pan b and is adapted to carry the removable grinding or polishing lap c, the latter being made of iron. Secured on the upper end of the spindle a is a hemispherical or like hollow member at which has a flat upper surface, the latter being surrounded in the example shown in Figure 1 by an annular flange e. The member (1 forms part of an impeller which has no bearing on the present invention and therefore does not warrant further description.

In carrying the invention into effect as shown in Figure 1, I employ an annular permanent magnet of appropriate diameter, the opposite poles being situated, at the opposite end faces of the annulus, and I secure the magnet to an iron disc g which at its centre is adapted to be secured by .a screw h to the upper end of the spindle a. The magnet f is secured to the disc 9 by any convenient medium such as white metal 2 introduced between an undercut annular shoulder on the upper side of the disc and a complementary recess in the magnet. Preferably at the centre of the upper side of the disc 9 I form or secure a hollow boss :i which surrounds the head of the screw it and which has its upper face coplanar with the outer face of the magnet f.

The iron lap c to be attached to the upper end of the spindle a has a flat undersurface which can be supported on the magnet f and boss y, and to locate the lap centrally it is formed with an annular lip or register it which can fit over the outer periphery of the magnet.

When the disc g with its associated magnet I is secured to the spindle a the disc lies in contact with the upper flat surface of .the member (1, and is surrounded by the flange e on this member. The magnet serves to detachably connect the lap to the spindle and also effect the required driving connection. Any-one of a plurality of laps as c of difierent forms may be used. When it is required to replace a lap by another the one in position is detached and the other is put in its place.

By means of the magnet above described the required connection between the spindle and lap is effected in a-very simple manner which ensures a rigid and serviceable support for the lap.

In the modification shown in Figures 2 and 3 the magnet ,f has the form of a short hollow cylindrical body which is closed at one end and open at the other, and which is provided at each of a pair of diametrically opposite positions with a longitudinalgap or slot n extending from the open to the closed end of the magnet, the latter being so magnetised that the end parts separated by the gaps or slots form north and south poles respectively. At the centr-e'of its closed end the magnet is provided with a hole through which the upper end of the spindle a can pass, this end of the spindle being screw-threaded for engagement by a nut m between which and the upper flat surface ofsthe member at the closed end of the magnet can be secured. In the interior. of the magnet is arranged a gun-metal or other non-magnetic metal bush p which is adapted at its inner end to surround the nut m and at its outer end to receive a boss q on the underside of the lap 0. The underside of the boss q and the upper ends of the spindle a and nut m are situated adjacent to each other, and are provided with registering transverse slots r, s for accommodating adjacent parts of a key piece which serves to effect a positive driving connection between the spindle and the lap c.

In the example shown in Figures 2 to 3 the magnet is intended to serve only or mainly for holding the lap on the spindle, the driving connection being provided by the key piece it.

Instead of employing the magnet above described for securing the lap in position it may be employed for securing to the upper end of the spindle a holder or clamp for the lap. An example of this is shown in Figures 5 and 6. In this example the magnet ,f is of similar form to that shown in Figures 2 to 4, and is likewise secured to the upper end of the spindle a by a nut m. For holding the lap'c, which is provided on its underside with a boss q, a gun-metal or other non-magnetic metal bush p is employed, one end portion of this bush being slotted at a: to render it resilient, and being adapted to be contracted on to the boss on the lap by a clamp or holder u. The other end portion of the bush 3) is adapted to be inserted into the interior of the magnet f, and to surround the nut m on the spindle a. The clamp a has the form of a split iron ring which can be tightened on to: the bush n by a bolt w, and which is adapted to lie between and in contact with the underside of the lap c and the adjacent end of the magnet j.

A driving connection between the spindle a and the bush p is efiected by a key y in the form of a peg which is secured radially to the upper end of the spindle and which can engage a longitudinal slot 2 in the inner end portion of the bush. The underside of the clamp or holder u is supported on and held by the magnet j andthe underside of the lap c is supported on the upper side of the clamp. The magnet f is intended to serve who-11y or mainly for holding the clamp u on the spindle a, and the rotational driving force is transmitted from the spindle to the lap 0 through the key y and the bush p.

The invention is not limited to the examples above described as subordinate details may be modified to suit different requirements.

Having thus described my invention what I claim .as new and desire to secure by Letters Patent is:

1. Means for detachably securing a grinding or polishing lap to the spindle of a machine of the kind specified, comprising a permanent magnet adapted to be secured to the upper end of the spindle, and to hold by magnetic attraction the removable lap or a clamp to which the lap can be attached.

2'. Means as claimed in claim 1, in which the magnet is of annular form and is attached to an iron disc which is adapted to be secured to the upper end of the spindle.

3. Means as claimed in claim 1, in which the magnet is of annular form and is attached to an iron disc which is adapted to be secured to the upper end of the spindle, the said disc being provided with a central boss having its outer face coplanar with the outer face of the magnet so that these faces can support the lap.

4. Means for detachably securing a grinding or polishing lap to the spindle of a machine of the kind specified, comprising a permanent magnet in the form of a hollow cylindrical body which is closed at one end and open at the other, and is provided with gaps which separate poles of opposite polarity at the open end of the magnet, the said magnet being adapted to. be secured to the upper end of the machine spindle, and to hold by magnetic attraction the removable lap or a'clamp to which the lap can be attached.

5. Means as claimed in claim 4, and having a non-magnetic bush adapted to be inserted into the magnet and to accommodate a boss on the lap.

, 6. Means as claimed in claim 4 and having in combination a non-magnetic bush adapted at one end to be inserted into the magnet and at the other end to be contracted on to a boss on thelap, and a clamp in the form of a split iron ring for contracting the bush on to the said boss, the said ring being adapted to lie in contact with the magnet.

7. Means as claimed in claim 4 and havinga key adapted by engagement with slots in adjacent parts of the spindle and lap to provide a driving connection between these parts.

8. Means as claimed in claim 4 and having DOUGLAS TAYLOR. 

